Super Bowl XLIX broke all sorts of records.
The New England Patriots' 28-24 victory over the Seattle Seahawks was the most watched TV show in U.S. history. Facebook saw 265 million posts, likes and comments during the big game, the most measured for any Super Bowl. Twitter generated over 28 million global tweets, making it the most tweeted Super Bowl ever.
There's no question about it: the world is becoming increasingly social during live television events, when viewers are eyeing the second screen, a mobile device, just as much as the first.
The challenge that big brands—which shelled out a record $4.5 million for a 30-second TV ad—face is maximizing their reach across both screens. Based on a CNBC survey, half of the 66 commercials shown during Super Bowl 49 featured a hashtag, giving viewers a nudge to bring the conversation from the big screen to the little one.
The hashtag grows up
What was noticeably missing alongside those 33 hashtags were the logos of social media companies such as Twitter and Facebook. Only four commercials included a Facebook logo, while Twitter was shown a mere three times. Snapchat's ghost icon, which made its Super Bowl debut this year, was shown once. Photo-sharing app Instagram got no on-air love.
"I'm so happy to see that brands have realized there is no need to place logos of social platforms at the end of a spot," says Jason Stein, founder of the social media agency Laundry Service. "If you want to use a commercial to drive conversation across social media, the spot should be designed for that and could include a hashtag as a call-to-action. A brilliant example of this was Procter and Gamble's #LikeAGirl ad."
The lack of social media icons may be also be a result of the hashtag exploding in use over the past few years.
"Hashtags are ubiquitous across all social platforms as a form of discovery, self-expression and a way to join a conversation, movement or group," said Stein.
In other words, when the content is powerful, viewers need not be told to place hashtags inside tweets or under Instagram photos anymore. In 2015, it's enough to simply place a hashtag in your ad and the social media world will take care of the rest.
Hitting social media home runs
Is the road to social media relevance and virality as easy as slapping a hashtag on a commercial or print ad?
Not quite.
"In order to make sure you're relevant on all screens, social media needs to play a large role in the conception and rollout of any major marketing program," said Stein. "This is called social by design."
Stein points to a new logo from Sonos, a manufacturer of wireless speakers, which gives viewers the effect of moving sound waves when scrolling up or down on the logo: "It was clearly driven by social media and optimized for feeds, without compromising the overall execution in any way."
One company that executed with social media in mind on Sunday night was BMW.
In a well-received spot, BMW showcased the advancement of technology using an NBC segment from 1994 in which hosts Katie Couric and Bryant Gumbel are seen discussing a new creation called the Internet. During the segment, the anchors briefly mention an email address, which most viewers dismissed as being part of the old footage from 1994. It turns out BMW quietly planted the email address into the segment and clever viewers who shot off an email to the address were told via a secret YouTube video that they could possibly win a car.
Avoiding social media pitfalls
Planning ahead may also help avoid social media disasters, which Nationwide quickly learned.
The insurance company ran a morbid ad about a boy unable to experience life's greatest pleasures because he died as the result of an accident. The social media world lit up negatively, questioning why the brand would run such a depressing spot. Nationwide defended the commercial, saying the sole purpose of the message "was to start a conversation, not sell insurance."
As Nationwide took heat on Twitter, rival State Farm opted to run a promoted tweet in Twitter user's streams, where it touted fire safety and prevention tips.
"State Farm got right what Nationwide got wrong," tweeted Stein. "Don't tell us that our kids will die, tell us how to prevent that from happening. Add value to my life.... The best marketing adds value in the form of inspiration, education or entertainment."
The lesson that brands are learning is clear: Social media and the second screen are just as, if not more, important than the ad you run on television during a big event.
"Social media represents the audience, the people who will see and react to your entire program, including the TV spot," Stein concluded. "There is nothing more important than the people for whom you are creating the spot or program. They should inform it."
Disclosure: CNBC's sister company NBC Sports broadcasts the Super Bowl.